Magneto-resistive sensors of the AMR (anisotropic magneto-resistive) type are known for measurement of rotational speed and for angular measurement in automotive applications. Further applications can be found in interesting consumer markets such as, e.g. mobile phones where much larger numbers are involved compared to the automotive industry. Examples of these new applications are small integrated pointer control devices (joysticks), accelerometers or tilt sensors and integrated microphones. These are typically integrated components which can be used in mobile phones or other portable devices such as laptops, PDA's, GPS systems, (remote) controls and digital camera's.
Until now most mobile phones have been equipped with “digital” joysticks which are based on a switching (on/off) mechanism. However, nowadays mobile phone manufacturers are looking into joysticks which provide a full analog signal instead of merely a switching signal, especially for gaming applications and web-browsing on their high-end telephones.
WO2006/035350, of the same inventor and incorporated herein by reference, discloses a sensor module using AMR sensor technology. The module comprises a joystick and a small, integrated, analog, magnetic sensor on a substrate. The joystick can be moved relative to the sensor die. The sensor is sensitive to movements of the joystick in the X-Y plane, i.e., the plane perpendicular to the stick when at rest, and to movements in the Z-direction, i.e., in the direction along the stick when at rest.
The sensor provides a signal proportional to these movements. As this sensor is sensitive to joystick movement perpendicular to the X-Y plane, it can be used for, e.g., a “Press-to-Select”-function or a “Confirm”-function.